Fig. (3) Antigenic comparison of native AltMV-MU and VLPs by indirect ELISA. Mouse antisera to AltMV-MU (a) and to VLP (b) were titrated on AltMV-MU (—■—) or VLP (—Δ—) adsorbed on microplate. (c) Western blot analysis of purified virions of AltMV-MU (lanes 1, 3 and 6), PVX (lanes 2 and 4), PAMV (lanes 5 and 7). Horizontal brackets indicate reactions of PVX antiserum (AS to PVX), AltMV-MU antiserum (AS to AltMV-MU) and PAMV antiserum (AS to PAMV) to AltMV-MU, PVX, PAMV virions.